Welcome to Android Central! The contacts might not be stored on the SIM, though--I believe that's only on older phones. Open the Contacts app, tap Menu, and look for the Import/Export option. Tap it, then tap Export. You should be able to export your Phone account contacts to a VCF or CSV file. You can then import them into Google Contacts. If you're using the new Google Contacts website on your computer, then click More on the left, then Import, and then CSV or Vcard. (Of course, you'll have to transfer the file from the phone to your computer first, via USB, or by uploading it to your Google Drive, then downloading it to your computer.)